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Tailings Cover Hydrology for the Central Manitoba Mine Site – Undergraduate Thesis for the University of British Columbia

Tailings Cover Hydrology for the Central Manitoba Mine Site – Undergraduate Thesis for the University of British Columbia

11 July 2013

July 11, 2013

Overview

The hydrology of a proposed cover system, under varying drainage layer conditions, for a mine site rehabilitation project located in Southeastern Manitoba was analyzed with the SoilVision Systems Ltd., SVFlux™ software. The proposed 1 m thick engineered soil cover included a 0.2 m thick highly permeable basal granular drainage layer, which was replaced with a man-made synthetic drainage system (DRAINTUBE™).

Four different levels of potential clogging of the man-made drainage layer were analyzed, equivalent to 99%, 90%, 50% and 0% clogging of the original material. The purpose of the analysis was to observe the flow dynamics and change trends in the hydrology of the engineered soil cover system located above the drainage layer, over a period of 10 years, and from there, estimate future trends in the cover system hydrology and its impacts.

Analysis

The SVFlux™ finite element modeling software was the main numerical tool used to model the hydrologic regime and complete the analyses. The software results include, among other, net percolation, flux, and saturation in each of the layers within the cover system. The plots were used for analysis and interpretation. Analyses took into consideration both external (climatic) and internal (soil properties), and the numerical method including transient conditions.

The hydrology of the soil cover was simulated with four different flow systems in the DRAINTUBE™ layer through varying the hydraulic conductivity in the DRAINTUBE™ layer to simulate a progressive clogging geotextile. The four cases below were drawn and modeled in SVFlux™ .

Case a) Assuming drainage layer is a clean granular drainage layer: this simulation would be equivalent to a 0% clogging of the pipes

The software presented various hydrological plots as outputs including a summary of the water balance, net percolation into the soil cover, saturation in each layer, and flux along the soil boundaries. Below is an example of the first case scenario plots showing, a hydrologic summary, saturation, flux, and net percolation versus time.

Conclusions

The modeling performed for each given case with SVFlux™ showed increasing flow trends over time as the hydraulic conductivity was reduced. The software results illustrated that the least desirable case and most extreme case showed that if the drainage system were to fail by becoming completely clogged in the long term; more than 50% of the drainage layer would be saturated and an increasing trend over 20 years could increase water percolation rates into the tailings. However, the system has some level of flexibility in terms of drainage layer clogging. Even with a 50% clogging of the drainage layer, the cover system would still be performing as designed, with a minor increase in saturation levels and limited increase in percolation rates. From this perspective, the system, as designed, has a built-in safety factor that allows good long term performance and should perform according to original requirements such as limiting erosion, limiting direct human exposure to tailings, shedding water away and supporting the vegetative cover.

I utilized the SVFlux™ package for the analysis of a one-dimensional seepage model for my thesis. I modeled a clogging drainage layer at a mine site closure. The software was easy to learn, quick to run, and results displayed comprehensive plots with all the information I needed for the analysis. I would highly recommend this software to other students completing their thesis.

Alexandra Nan, Student, Geological Engineering, University of British Columbia

If you are interested in this type of analysis, the SVFlux™ software package is available. Please visit our ordering page for pricing and purchase information, or contact us directly.

Testimonials

"I would like to thank you for all the support and the interest that I got from your team regarding this matter. I was able to successfully finish my project with the help of your technical support and managed to graduate achieving a high grade on the project I did. The software is extremely helpful and wasn't complicated and I look forward to future for more work and experience with your software. Thank you for your help and support."

Abdul Hadi Ahmad Al Klaib

Student at Bangladesh University of Engineering and Technology (BUET)

"I have been using SoilVision's SVOFFICE™ software for research and training purposes for a number of years now. Myself and my colleagues have developed a number of training modules in this software, and have been using these to teach limit equilibrium and flow modeling to undergraduate students in the civil, environmental and mining engineering streams.

In my opinion, this software is easy to learn and fun to use. The built-in tutorials are sufficient to get one started. With these tutorials, my students were generally able to complete their analyses with minimal involvement on my side.

Based on my own experience, it takes around a month of full-time use to become reasonably competent with the software (provided that one understands the theoretical underpinnings of this type of analysis) - a short learning curve, compared to other products of similar complexity. The interface is intuitive enough for me to figure out things on my own, and I rarely had the need to ask for help.

I don't generally like praising anything excessively, and I don't post particularly glowing reviews for anything. Having said that, I must mention the SoilVision support. At some point during my research, I was conducting a number of replication studies for my thesis. In that period, I must have emailed SoilVision's support anywhere from 2 to 5 times a day, with fairly complex (and sometimes very dumb) questions. I always got a response by the end of the day, and a resolution within a couple days at most. In a number of urgent cases (such as during a tutorial session with a classroom of students) I called them directly on the phone and, with senior product engineers involved, had the issue addressed in minutes."

Elena Zabolotnii, PEng MEng

PhD Candidate, Geotechnical Engineering at University of Alberta

"We have allowed our students the choice of using multiple Geotechnical software suites in our Dam Design and other Geotechnical courses. Our students consistently gravitate towards SoilVision software as being the most modern and user-friendly."

Gilson Gitirana Jr.

Associate Professor at Federal University of Goiás

"I've been a geotechnical engineer for more than 25 years and SoilVision has the best tech support I have ever worked with. I truly appreciate their patience and help over the past year."

Donald Tharp

Principal Engineer at Ninyo & Moore

"Peter Brett Associates have been looking to update our existing slope stability software over the last year. After extensive research and trials, SVSLOPE® developed by SoilVision Systems Ltd. was found to meet all our existing and future design requirements. Its ease of use for modeling simple as well as complex geological and geometrical problems was a critical factor in our assessment as well as the incorporation of design to the Eurocodes. Their customer support has been faultless and their willingness to develop the software to meet our own specific design requirements is a most gratifying added bonus."

"We love the fact that SVSLOPE® is part of an integrated suite of software and that, if required, 3D analysis can be undertaken. We would recommend this product to other geotechnical consulting firms."

Asmi Desai

Principal Engineer at Peter Brett Associates LLP

"We have been using SVSLOPE® and SVFLUX™ for the past year and have found them to be efficient and productive engineering tools which have allowed us to offer our services in an efficient manner. The capability of automated increased discretization of the mesh is an absolute benefit to our modeling, reducing time and effort. We have found the software quick and easy for our engineers to train and utilize. I would recommend this product to other geotechnical consulting firms."

Barry L. Carlson, P.E.

President at InTerraLogic

"The software is well documented and comes with number of useful example models. We were able to quickly begin creating models after a short review of the user interface and going through the available on-line webinars. The software offers solid benefits of less conservatism and the ability to model real geometry."

Steven A. Haire, P.E.

Chief Geotechnical Engineer at Ninyo & Moore

"This new software for stability analysis includes a number of state-of-the-art options for probabilistic slope stability analysis. This feature, combined with comprehensive deterministic analyses, will provide new opportunities to build confidence in the results of a site-specific analysis.”

Prof. Dirk van Zyl, Ph.D., P.E.

Professor of Mine Life Cycle Systems at University of British Columbia

"I'm excited to see the release of this new and innovative product. I look forward to and encourage the application of this software on additional geotechnical projects.”

Prof. Ward Wilson, Ph.D., P.Eng.

Mining Chair at University of British Columbia

"In consulting engineering practice, I am increasingly made aware of the important and beneficial role that modeling the unsaturated soil zone can play in providing the client with the best possible engineered solution. The SoilVision software has made it possible to readily estimate and incorporate unsaturated soil properties into the modeling of saturated / unsaturated soil systems.”

Del Fredlund, O.C., Ph.D., P.Eng.

Senior Project Engineer at Golder Associates

"The use of SVSLOPE® software as part of a research project on clay slopes under seismic conditions with the Université de Sherbrooke has been incredibly easy and effective. The continuation of this research with SoilVision is promising, with technical support, which was present at the right time, as well as a passionate geotechnical team supporting the project.”